Class II Special Controls Guidance Document: Intervertebral Body Fusion Device

Name of Guidance:
Class II Special Controls Guidance Document: Intervertebral Body Fusion Device

Status of Guidance:
Final

Name of Organization:
US Food and Drug Administration
Center for Devices and Radiological Health

Date of Guidance:
June 2007

Target Audience:
Sponsors submitting 510(k) applications for intervertebral body fusion devices

Laws and Regulations Referenced:
21 CFR 50 Describes how human subjects are to be protected in clinical trials
21 CFR 56 Describes the role of institutional review boards
21 CFR 801 Describes the labeling requirements for medical devices
21 CFR 807 Describes establishment registration and device listing for manufacturers and importers of medical devices
21 CFR 812 Outlines the requirements of an Investigational Device Exemption
21 CFR 820 Describes quality control for medical device manufacturing
21 CFR 888 Defines various orthopedic medical devices
Federal Food, Drug, and Cosmetic Act, Section 514 Describes performance standards for medical devices

Definitions:
Intervertebral body fusion device – A piece of medical equipment that is implanted in the spine to help two adjacent vertebrae fuse together into a single unit.

Class II (special controls) – The FDA classification for medical devices that pose moderate risk to a patient (as opposed to Class I General Controls, which pose minimal risk, and Class III Premarket Approval, which pose greatest risk).

510(k) submission – The application under Section 510(k) of the Federal Food, Drug, and Cosmetic Act, which provides a streamlined way to request FDA approval for a device that is substantially similar to another device the FDA has already approved.

Background:
Certain disorders of the spine may be treated by surgery that permanently fuses two or more vertebrae together. A device is implanted in the spine to help the vertebrae become one fixed unit. This device is called an intervertebral body fusion device. The US Food and Drug Administration (FDA) groups medical devices into three categories depending on how much risk they pose to patients. Class I devices involve the least risk, Class II devices involve moderate risk, and Class III devices involve the most risk. Intervertebral body fusion devices fall under Class II and require “special controls,” meaning their safety and effectiveness must be demonstrated in ways that are specific to their design and intended use. This guidance provides device makers with suggestions on how to demonstrate the safety and effectiveness of their proposed intervertebral body fusion devices.

Summary:
When seeking permission from the FDA to market a new intervertebral body fusion device, the device maker must submit a 510(k) application. This application describes the device in detail, compares it to similar devices that are already in use, and provides the results of safety testing. The goal of the application is to demonstrate that the device is “substantially equivalent” to a device the FDA has already approved. If the FDA agrees that the device is equivalent, the device maker does not have to test it in humans before marketing.

Intervertebral body fusion devices contain material that encourages bone growth. This speeds the process of fusion. This guidance applies only to devices that contain bone graft material, not to those that contain therapeutic biologics (for example, bone morphogenic protein). Those that contain biologics fall under Class III and require human testing before marketing.

The FDA recommends that device makers submit the following information to demonstrate “substantial equivalence” of their intervertebral body fusion devices:

Device description. This detailed description should include specifications, engineering drawings, and photographs of the device attached to a spine model. It should identify all materials used in the device, typically certain metals and plastics. It should also describe any special surgical instruments that are used to implant the device.

Risk analysis. Certain risks that are common to all surgeries must be addressed. These include infection, pain, and tissue injury. Other risks that are specific to the fusion device must also be described, such as injury to the vertebrae, and the risk that fusion will not occur.

Device materials. Two of the biggest concerns about spinal implants are whether they leach foreign substances into the body, and whether tiny fragments may break off over time and cause a harmful response. Device makers must test for these issues and report on the results. They must also simulate the aging of the devices to see whether results change over time.

Mechanical performance. The human spine is capable of a wide range of movement in a variety of directions. Therefore, spine implants must be able to withstand mechanical forces without breaking, slipping out of place, or otherwise failing. The FDA recommends that a device be able to withstand 5 million repetitions of a mechanical test without failure.

Animal testing. If a fusion device is to be used to treat a new disorder, if its design is considered novel, or if it is shown to produce particles that are different than previous devices, the FDA may require safety testing in animals. Animal testing may also be required if the materials used in the device have not been previously tested in the spine or if mechanical testing raises safety concerns.

Human testing. Sometimes the FDA will require a new intervertebral body fusion device be tested in humans. This typically happens when the device uses a new technology, is designed to treat a new disorder, or when animal testing raises safety concerns. In such cases, the device makers must apply for Investigational Device Exemptions.

As part of the 510(k) application, the device maker should also indicate whether the device will be packaged in sterile form (preferred) or whether it must be sterilized before implantation. They should also provide proposed labeling describing when and how the device is used, in what areas of the spine it may be implanted, as well as warnings and precautions.

Rationale:
The FDA uses the 510(k) provision to reduce the time and cost required to market a medical device that is substantially similar to one that is already FDA-approved. The goal of this system is to bring better devices to market faster while ensuring patient safety. This guidance addresses safety concerns that are specific to intervertebral body fusion devices, outlining the areas that device makers should cover in their 510(k) applications.

Resulting Recommendations:

· A successful 510(k) application for an intervertebral body fusion device must show that the device is substantially equivalent to another such device already approved by the FDA.

· The application should provide detailed specifications of the design and materials used in the device.

· The applicant should analyze the risks involved in the use of the device and explain how they have minimized each risk.

· All materials used in the device should be tested to determine whether they pose a risk of leaching foreign substances into the body.

· Materials should also be tested to determine whether their performance differs after long-term implantation.

· The device should be tested mechanically to determine that it will withstand the loads present in the human spine without failure.

· Animal testing may be required to demonstrate safety of materials and mechanics of the device, particularly if it is to be used to treat new conditions, or its design or mechanics differ substantially from previous devices.

· Human testing may be required through the IDE process if substantial equivalence of the device is not established through mechanical and animal testing.

Impact:
This guidance helps the makers of intervertebral body fusion devices write successful applications that address the FDA’s specific concerns about their product. This should enable device makers to bring their products to market faster, giving patients in the US access to the latest versions of these devices in a timely manner.